Decoupling web

ABSTRACT

The invention relates to a decoupling web ( 1 ), in particular intended for use for a surface covering structure ( 2 ) which can be covered with covering elements, preferably tile coverings, having a carrier web ( 3 ) and a multiplicity of nubs ( 5 ) projecting from the carrier web plane ( 4 ), the carrier web ( 3 ) having as material a, preferably thermoplastic, plastic. According to the invention, it is provided that the carrier web ( 3 ) comprises as material a copolymer comprising ethylene and vinyl acetate, in particular a copolymer of ethylene and vinyl acetate, preferably ethylene-vinyl acetate (EVA), and/or consists thereof.

The invention relates to a decoupling web with a carrier web and aplurality of nubs projecting from the plane of the carrier web, thecarrier web having as material a, preferably thermoplastic, plastic. Thedecoupling web is in particular intended for use for a surface coveringstructure which can be covered with covering elements, preferably fortile coverings.

The term “decoupling” is understood to mean the reduction of shearstresses and/or stress peaks between two layers arranged in a firm bond.Effective decoupling thus prevents shear stresses and/or stress peakspresent in one of the layers from being transferred to the other layerof the composite structure and causing damage there.

Decoupling webs of the aforementioned type are used, for example, in theconstruction industry when laying floor covering elements, such asceramic tiles, in particular for decoupling, sealing and/or for vapourpressure compensation. In this case, the decoupling webs are laid on anunderground, in particular glued, and form the supporting surface forthe floor covering elements. Tiles are laid in particular on youngscreed using the thin-bed method. If no decoupling membrane is laidbetween the tiled floor and the young screed, then in the event ofshrinkage of the screed the tiles, in particular due to their lowcoefficient of expansion, could not follow the movement of the screed,so that shear stresses arise which could ultimately lead to detachmentor even tearing of the tiles. Decoupling webs are also required whenlaying coverings on particularly critical undergrounds, such as oldwooden floors. A decoupling web of the type mentioned above compensatesfor these shear stresses by deformation, which is why there is no needto fear damage to the composite structure. In most cases, decouplingmembranes are made of foil-like plastic, i.e. a flexible plastic layerthat deforms under the influence of external forces. The material isusually selected in such a way that it is low in emissions, especiallywith regard to pollutants.

On the side of the decoupling membrane facing away from the floorcovering elements, a fleece is usually provided, which can be firmlybonded to the carrier web. The fleece can be arranged on an undergroundwhen the decoupling web is laid and can be bonded to the underground. Anadhesive layer may therefore be provided between the underside of thedecoupling membrane facing away from the covering elements and theunderground.

Subsequently, a thin layer of tile adhesive, also known as adhesivemortar or bonding layer, is usually applied to the support plane of thedecoupling web to fix the floor covering elements to the decoupling web.It is understood that instead of a tile adhesive, an equally suitableadhesive or fastening layer and/or material may ultimately be provided.In this regard, tile adhesives are usually combed with a toothed trowelor a toothed smoothing trowel and a different tile adhesive is useddepending on the area of application and/or the underground. Forexample, a reactive resin adhesive, a cementitious thin-bed mortar, acasein tile adhesive or a dispersion adhesive is used as the tileadhesive.

After the tile adhesive has been applied to a decoupling web, theindividual flooring elements and/or tiles are laid on the tile adhesive.During application, the tile adhesive penetrates into the depressions ofthe decoupling web and hardens.

With decoupling webs of this type, the connected floor covering elementsare separated from the underground and mechanically decoupled. Due tothe arrangement of the nubs transverse to the longitudinal direction andin the longitudinal direction of the carrier plate, channels resultwhich extend over the entire carrier plate. These channels interact withthe nubs in such a way that they absorb and compensate for mechanicalstresses and, in particular, shear stresses. This stress on the flooringelements can be generated due to temperature and humidity influencesand/or due to a weight load.

In the manufacture of such decoupling webs, a mould is used which hasprojections corresponding to the recesses and/or nubs. However, thedemoulding of the moulding tool and the decoupling sheet is usuallyproblematic. Furthermore, the decoupling web can easily be damagedduring demolding, especially if the protrusions of the mold have sharpcorners that cut into and/or tear the usually still soft decoupling webmaterial. In practice, attempts are made to solve the latter problem byproviding the corners of the tool projections with a radius.

The adhesive tensile strength of the nub membranes known inpractice—without the use of additional layers—does not usually meet therequirements needed for the use of the decoupling web.

Tensile adhesion strength, sometimes also referred to as pull-offstrength, is a characteristic value used to evaluate the adhesion and/orbonding of layers to surfaces, in particular of the tile adhesive to thedecoupling web. The adhesive tensile strength can be determined by meansof an adhesive tensile test.

It is now an object of the present invention to provide a decoupling webhaving improved adhesive tensile strength.

According to the invention, the aforementioned task is at leastsubstantially solved in a decoupling web of the type mentioned above inthat the carrier web comprises as material a copolymer comprisingethylene and vinyl acetate and/or consists thereof. Quite preferably,the copolymer comprising ethylene and vinyl acetate is formed as acopolymer of ethylene and vinyl acetate, preferably ethylene-vinylacetate (EVA, EVAC).

It goes without saying that special features, characteristics, designsand embodiments as well as advantages or the like which are set outbelow—for the purpose of avoiding unnecessary repetition—in relation toonly one aspect of the invention, naturally apply mutatis mutandis inrelation to the other aspects of the invention without the need forexpress mention.

Furthermore, it goes without saying that in the following specificationof values, numbers and ranges, the relevant specifications of values,numbers and ranges are not to be understood in a limiting manner;rather, it goes without saying for the person skilled in the art that,depending on the individual case or application, deviations from thespecified ranges and/or specifications can be made without leaving thescope of the present invention.

In addition, it applies that all values or parameters or the likementioned in the following can in principle be determined or determinedwith standardized or explicitly stated determination methods or withdetermination methods familiar to the skilled person in this field.

Furthermore, it goes without saying that all weight or quantity-relatedpercentages are selected by the person skilled in the art in such a waythat the total results in 100%.

Having said this, the present invention will be described in more detailbelow.

In particular, it is understood that the carrier web may also comprisethe copolymer comprising ethylene and vinyl acetate, preferably EVAC,only “proportionally”. The material of the carrier web can also compriseanother, preferably thermoplastic, plastic.

Furthermore, it is particularly understood that a plurality, inparticular at least two, of further, preferably thermoplastic, plasticmaterials may also be provided.

According to the invention, it has been found, to the complete surpriseof the skilled person, that the copolymer comprising ethylene and vinylacetate can significantly improve the mechanical properties of thedecoupling web compared to decoupling webs known from the prior art.Thus, on the one hand, a significantly better adhesion, preferably by upto 60%, can be achieved compared to decoupling webs known in practice.The adhesion is improved in particular to the fleece and/or to the tileadhesive. Moreover, the decoupling web is not only substantially moreflexible, but also exhibits better decoupling properties than decouplingwebs known in practice. Due to the flexibility, for example, thepackaging, in particular into rolls, of the decoupling web can be madeeasier, which reduces the effort required for storing the decouplingweb.

In particular, the improved adhesion of tile adhesive to the decouplingweb can also improve the adhesive tensile strength of the entiredecoupling web.

The term “ethylene vinyl acetate” (EVA, also known as EVAC) ultimatelyrefers to a group of copolymers formed by the polymerization of ethyleneand vinyl acetate. Despite the strong branching of the chain molecules,the structure of ethylene vinyl acetate is crystalline only in a fewplaces. With a corresponding vinyl acetate content, the ethylene vinylacetate can be partially crystalline and thermoplastic. A translucentformation of the ethylene vinyl acetate is also known. The density andother properties are particularly dependent on the vinyl acetate content(VAC). At a lower vinyl acetate content (VAC), the ethylene vinylacetate is more translucent, tougher, more flexible and moredimensionally stable under heat compared to PE-LD. A higher vinylacetate content reduces strength, stiffness and chemical resistance.

The copolymer according to the invention comprising ethylene and vinylacetate exhibits a flexibility at least substantially similar to rubberand ultimately resembles soft polyvinyl chloride, in particular in itsproperty profile. At the same time, however, tear and impact resistanceas well as light transmission and, in particular, gloss increase.

According to the invention, it is preferred that the properties of thedecoupling membrane with respect to waterproofing, vapour pressurecompensation and good drying are further ensured. The decouplingmembrane according to the invention is waterproof, enables good vapourpressure compensation and also good drying. The vapour pressureequalisation and the drying can also be improved by the fact that thechannels extending over the decoupling web, which run between theadjacent studs, are connected to one another indirectly and/or directlyfor the entire nub web.

According to the invention, the decoupling effect is advantageouslydesigned in such a way that, on the one hand, no cracks are formed inthe surface of the covering facing away from the decoupling web and, onthe other hand, possible cracks in the underground, which in particularonly occur after the decoupling web has been laid, do not show in thetile adhesive layer and/or the covering elements. Consequently, animproved load distribution can be achieved by the addition of EVAaccording to the invention.

Furthermore, the decoupling web according to the invention enables ahigh winding capability, so that the decoupling web can be easily rolledup, preferably for transport. Furthermore, the decoupling web accordingto the invention can have a high torsional stiffness and/or a hightorsional stiffness, so that the decoupling web cannot be kinked and/ortwisted, in particular by 90°.

Furthermore, it was found in tests carried out that, in addition to itsexcellent decoupling properties, the decoupling web according to theinvention also exhibits very good impact sound insulation. This effectis also the result of the addition of the copolymer comprising ethyleneand vinyl acetate according to the invention.

In a particularly preferred embodiment of the present invention, thecarrier web comprises at least one thermoplastic polymer and/orelastomer as a further material. In particular, the thermoplasticpolymer and/or elastomer may be hard polyethylene (HDPE), polyethylene(PE) and/or polypropylene (PP). Accordingly, the material of the carrierweb may comprise another thermoplastic polymer material in addition tothe copolymer comprising ethylene and vinyl acetate. In particular, thecopolymer comprising ethylene and vinyl acetate may be blended with thefurther material. Alternatively or additionally, it is possibleaccording to the invention for the further material to have a massfraction in the material of the carrier web of at least 20 wt. %,preferably between 30 wt. % to 99 wt. %, more preferably between 40 wt.% to 95 wt. %, further preferably between 50 wt. % to 80 wt. %.

In tests carried out, it has been found that by adding the copolymercontaining ethylene and vinyl acetate to thermoplastic materials knownin practice for the carrier web, the essential properties of thedecoupling web, in particular the decoupling properties and the adhesivetensile strength, can be significantly improved, preferably by up to50%.

Preferably, the copolymer comprising ethylene and vinyl acetate, inparticular the ethylene-vinyl acetate (EVAC), has a mass fraction in thematerial of the carrier web of at least 5 wt. %, preferably between 10wt. % and 80 wt. %, more preferably between 20 wt. % and 60 wt. %, andin particular at least substantially between 25 wt. % and 55 wt. %.Depending on the proportion of the copolymer comprising ethylene andvinyl acetate in the material of the carrier web, in particular inrelation to the further thermoplastic material, the properties, inparticular the adhesive tensile strength and/or the decouplingproperties, of the decoupling web can be adjusted accordingly.Individual adaptation to the respective customer requirements and/or theproperties intended for the respective use can then be readily possible.

Furthermore, in another preferred embodiment of the invention, it isprovided that the copolymer comprising ethylene and vinyl acetate has avinyl acetate content of at least 5%, preferably between 10% to 50%,more preferably between 12% to 40%, further preferably between 16% to30%, and in particular at least substantially between 25% to 29% , inparticular based on the copolymer comprising ethylene and vinyl acetate.

Depending on the proportion of vinyl acetate, the properties of thecopolymer can be adjusted or varied accordingly, in particular dependingon the respective customer requirements, use specifications or the like.Macroscopically, the modulus of elasticity of the material, inparticular of the copolymer comprising ethylene and vinyl acetate,should decrease with an increasing proportion of vinyl acetate (VAC). Ata vinyl acetate of about 40 to 70 wt. %, the copolymer comprisingethylene and vinyl acetate is largely amorphous, whereas at a vinylacetate of below 30 to 40 wt. %, the copolymer comprising ethylene andvinyl acetate is semi-crystalline and thermoplastic. Preferably, it isprovided that the copolymer comprising ethylene and vinyl acetate isthermoplastic, so that in particular the vinyl acetate content is below40 wt. %, based on the copolymer comprising ethylene and vinyl acetate.

In experiments carried out, it has been found in the course of theinvention that with a vinyl acetate content of 28%+/−2%, the propertiesof the overall decoupling web could be further improved as compared toother vinyl acetate contents. Moreover, the copolymer containingethylene and vinyl acetate with a vinyl acetate content of 28% is notonly inexpensive but also readily available, which greatly simplifiesthe production of the carrier web. The copolymer comprising ethylene andvinyl acetate, in particular ethylene-vinyl acetate, having a vinylacetate of about 28% is also referred to as “EVA28”.

In addition, it has been found during the development of the inventionthat the decoupling properties and/or the adhesion, in particular theadhesive tensile strength, can be significantly improved by a multilayerstructure of the carrier web compared to the decoupling webs known inthe prior art. In this regard, a multilayer structure of the carrier webmay comprise layers differing from one another with respect to adhesion,adhesive tensile strength, elasticity and/or elongation at break.Consequently, it is possible to selectively adjust the mechanicalproperties of the decoupling web by means of the layer structure of thecarrier web, in particular as a function of individual customerrequirements.

Preferably, the carrier web has an at least two-layer layer structure,wherein at least two layers (A, B) have a material composition thatdiffers from one another. The differing material composition has aneffect in particular with regard to differences in flexibility,elasticity, adhesion and/or adhesive tensile strength.

Accordingly, this aspect of the multilayer construction of the carrierweb is particularly advantageous in combination with the addition of thecopolymer comprising ethylene and vinyl acetate to the material of thecarrier web and/or as the material of the carrier web.

Accordingly, the copolymer comprising ethylene and vinyl acetate can beincorporated both in the entire carrier web, in particular in each layerof the carrier web, or also only in at least one layer of the carrierweb. This allows a high adaptability of the carrier web to differentpurposes or but also environments of use. For example, the outer side ofthe carrier web facing the nonwoven and/or the tile adhesive can beprovided with and/or mixed with the copolymer comprising ethylene andvinyl acetate, whereby the adhesion to the nonwoven and/or the tileadhesive can be significantly improved.

Particularly preferably, at least one layer—either layer A and/or layerB—of the carrier web comprises and/or consists of the copolymercomprising ethylene and vinyl acetate, in particular ethylene-vinylacetate (EVAC). Particularly preferably, at least one outer layercomprises and/or consists of the copolymer comprising ethylene and vinylacetate, as previously mentioned. Preferably, a layer structure in theform A-B-A or A-B is provided.

In a layered structure of the form A-B-A, the outer layers A, A may beat least substantially identical in construction—i.e. the same materialcomposition and/or the same layer thickness.

In principle, a layered structure in the form A-B-C would also beconceivable, in which case an outer layer C would be different from theouter layer A. In this case, the outer layer C can have a differentproportion of the copolymer comprising ethylene and vinyl acetate orcontain no copolymer at all comprising ethylene and vinyl acetate.

The aforementioned layer structures enable, according to the invention,that the copolymer containing ethylene and vinyl acetate is ultimatelyused in those layers—and contributes to the improvement of themechanical properties there—where it is also “needed”. For example, itis not immediately necessary to integrate the copolymer comprisingethylene and vinyl acetate in the middle layer (layer B), although thisis of course not excluded according to the invention.

The outer sides and/or outer layers of the backing sheet may comprisethe copolymer comprising ethylene and vinyl acetate, it being possible,if required, for only one outer side and/or one outer layer of thecarrier web to comprise the copolymer comprising ethylene and vinylacetate. By integrating the copolymer comprising ethylene and vinylacetate into the outer layers, in particular the adhesion of the carrierweb to nonwoven and/or the adhesion to the tile adhesive, in particularthe adhesive tensile strength of the carrier web, can be significantlyimproved compared to the decoupling webs known in the prior art.

In a further preferred embodiment, it is provided that only one outerlayer (A) and/or the outer layers ((A, A) and/or (A, C)) comprise(s) thecopolymer comprising ethylene and vinyl acetate. Alternatively,according to the invention, it is possible that each layer ((A, B)and/or (A, B, C)) of the layered structure (for example, A-B, A-B-Aand/or A-B-C) of the carrier web comprises and/or consists of thecopolymer comprising ethylene and vinyl acetate. Ultimately, thecopolymer comprising ethylene and vinyl acetate can be input and/orintroduced precisely into the layers in which the properties, inparticular the mechanical properties, are to be improved.

In tests carried out, it has been determined that the layer (A, B, C)comprising the copolymer comprising ethylene and vinyl acetate has amass fraction of the copolymer comprising ethylene and vinyl acetate inthe material of the layer (A, B, C) of at least 5 wt. %, preferablybetween 10 wt. % and 80 wt. %, more preferably between 20 wt. % and 60wt. %, further preferably between 25 wt. % and 55 wt. %. According tothe invention, it has been found that the aforementioned mass fractionsof the copolymer comprising ethylene and vinyl acetate particularlyimprove the adhesion and the decoupling properties of the entiredecoupling web and in particular of the carrier web. In particular, atleast one thermoplastic polymer and/or elastomer is provided as furthermaterial in the layer (A, B, C) comprising the copolymer comprisingethylene and vinyl acetate. Very preferably, HDPE, PE and/or PP isprovided as the thermoplastic polymer.

Preferably, the copolymer comprising ethylene and vinyl acetate isblended with the further material of the layer (A, B, C) comprising thecopolymer comprising ethylene and vinyl acetate with the furtherthermoplastic material. The further material may in turn have a massfraction of the material of the carrier web and/or of the mass fractionof the material of the layer (A, B, C) of at least 20 wt. %, preferablybetween 30 wt. % to 99 wt. %, more preferably between 40 wt. % to 95% byweight, further preferably between 50 wt. % to 80 wt. %.

Very preferably, it is provided that the mass fractions of the furtherthermoplastic material added to the mass fractions of the copolymercomprising ethylene and vinyl acetate in the layer (A, B, C) comprisingthe copolymer comprising ethylene and vinyl acetate add up to 100% byweight. This means that the layer (A, B, C) comprising the copolymercomprising ethylene and vinyl acetate comprises only one otherthermoplastic material in addition to the copolymer comprising ethyleneand vinyl acetate.

Furthermore, in a very particularly preferred embodiment of the presentinvention, it is provided that the outer layer (A) and/or the outerlayers (A, A) and/or the outer layers (A, C) have at least 10%,preferably between 10% to 90%, further preferably between 40% to 60% andin particular at least substantially 50%, of the layer thickness of afurther, in particular central, layer (in particular layer B). Theadvantage of the above-mentioned ratios is that the outer layers (layerA or layer C) can have a smaller layer thickness and thus a smallerproportion of material—measured in terms of the total proportion ofmaterial of the carrier web—in comparison with the “main layer” orcentral layer B. In the course of the development of the invention ithas been found that for the improvement of the adhesion and thedecoupling properties according to the invention by the addition of thecopolymer containing ethylene and vinyl acetate, an addition in theouter layers of the layer structure is sufficient.

A multilayer structure of the carrier web can be readily produced byextrusion molding. Thus, a coextrusion die and/or a multilayer die maybe used for applying or producing the carrier web. Alternatively oradditionally, it may be provided that the carrier web can be produced bythermoforming thermoplastic material.

In particular, the extrusion die may be a multi-layer die which providesa layer structure in the form A-B-A or A-B-C or A-B.

Alternatively or additionally, according to the invention, it may beprovided that a multilayer blown film is produced which is formed in athermoforming process, in particular after its production.

Furthermore, the aforementioned preferred ratios of the layerthicknesses of the layer structure of the carrier web can ensure thelowest possible material consumption of the copolymer comprisingethylene and vinyl acetate, while at the same time ensuring theimprovements according to the invention associated with the copolymercomprising ethylene and vinyl acetate compared to the prior art.

Preferably, the carrier web, in particular the decoupling web, has anadhesive tensile strength of greater than 0.1 N/mm², preferably greaterthan 0.2 N/mm², more preferably between 0.2 N/mm² and 5 N/mm².

The adhesive tensile strength is determined by means of a special test,which is also called adhesive tensile test and/or tear-off test. DIN EN12004:2017-05 has a specification for determining the adhesive tensilestrength under defined conditions.

Adhesive tensile strengths of the order of magnitude mentioned aboveenable, in particular, good adhesion to the underground and also ensuregood adhesion to the tile adhesive. According to the invention, theadhesive tensile strength of the carrier web can be increased by addingthe copolymer comprising ethylene and vinyl acetate.

In a further preferred embodiment of the present invention, it isprovided that the carrier web, in particular the decoupling web, has amodulus of elasticity of less than 100 GPa, preferably less than 10 GPa,more preferably between 0.01 to 5 GPa and preferably between 0.05 to 2.5GPa. The modulus of elasticity is a material characteristic value frommaterials engineering, which ultimately describes the proportionalrelationship between stress and strain during the deformation of a solidbody in the case of a linear-elastic behavior. The modulus of elasticityis the proportional elastic constant in Hooke's law. The higher themodulus of elasticity, the less elastic and/or flexible the solid body.

In particular, the modulus of elasticity can be determined according toEN ISO 527-1 (as of May 2019). The aforementioned standard is a Europeanstandard for plastics for the determination of tensile properties, whichcan be determined by a tensile test with a tensile testing machine.

Furthermore, the decoupling web may comprise a fabric and/or non-wovenlayer, in particular on the side opposite of the carrier web plane. Thefabric and/or non-woven layer may be firmly bonded to the carrier web,in particular wherein the fabric and/or non-woven layer is laminated tothe carrier web. The adhesion to the nonwoven layer can be improved,preferably by up to 30%, compared to the prior art, in particular byusing the copolymer comprising ethylene and vinyl acetate. A spunbondednonwoven can be used as the nonwoven, in particular wherein a spunbondednonwoven comprising a thermoplastic is provided, preferably apolypropylene spunbonded nonwoven.

The nonwoven may ultimately correspond to the nonwovens already known inpractice, which are arranged on a carrier web.

Furthermore, in another embodiment of the invention, it may be providedthat the nubs are spaced apart and, preferably, transverse to thelongitudinal direction and in the longitudinal direction of thedecoupling web. In this respect, the nubs may be spaced from the carrierweb plane and from a lower nub plane formed by the nub end face.Ultimately, the nubs constitute so-called “depressions” in the carrierweb, so that ultimately an upper carrier web plane results whichcomprises a plurality of depressions formed by the nubs, so that the nubend faces form the lower nub plane. According to the invention, theaforementioned formation of the nubs enables “channels” to be formedwhich contribute to decoupling.

According to the invention, different shapes of the nubs areconceivable. For example, an at least substantially cuboidal nub may beused. A nub with an at least substantially three-legged shape—as seen incross-section—is also conceivable.

In particular, elliptical, preferably round and/or oval, shapes—seen incross-section—of the nub are also conceivable.

The nubs formed as recesses ultimately form side walls of the nubs,which connect the nub end faces to the carrier web plane.

Very particularly preferably, it is provided that the nubs and/or atleast one nub have, at least in sections, an undercut, preferably on atleast one side wall of the nub. The undercut serves to improve theadhesion and/or the bonding of the tile adhesive.

According to the invention, it is understood that the decoupling web isfilled after being laid on an underground, in particular wherein theouter side of the carrier web comprising the fleece or fabric layer isarranged against the underground. Filling out can be carried out inparticular with tile adhesive. A surface covering, in particular tiles,can then be arranged on the tile adhesive. The tile adhesive canpreferably be introduced into the nubs and/or into the depressionsformed by the nubs and filled out over the decoupling web.

The tile adhesive penetrates the undercut during the filling process,resulting in improved adhesion. This in turn leads to a fixation and/orpositive locking of the tile sheet and/or covering elements to beapplied to the decoupling web.

In a particularly preferred embodiment of the invention, the formationfor forming the undercut on the inside of the nub is crescent-shaped orarcuate and/or arcuate-section-shaped and/or crescent-shaped. Inparticular, this arcuate section-shaped formation results in improveddemolding during the manufacture of the decoupling web. In contrast toangular undercuts, a rounded or sickle-shaped form of the undercutadvantageously ensures an easy separation between the forming tool andthe decoupling web. Thus, the decoupling web in particular cannot bedamaged during demoulding. Moreover, the rounded undercuts preferablyserve to ensure that the stress peaks of the shear stress of the liningelements are reduced and/or evenly distributed on the decoupling web.

Very particularly preferably, it is provided that the nubs, inparticular all the nubs, are at least substantially identical inconstruction.

In another preferred embodiment, the height of the nubs is between 1 mmand 5 mm, preferably 2 mm to 4 mm, more preferably 2.5 mm to 3.5 mm.This comparatively low stud height allows for a low overall layerbuild-up and implies the reduced amount of tile adhesive required forthe connection between the decoupling web and the covering elements.Nevertheless, due to the addition of the copolymer comprising ethyleneand vinyl acetate according to the invention, a strong bond is achievedbetween the tile adhesive and the decoupling web while simultaneouslyachieving an excellent decoupling effect.

In another preferred embodiment, the clear distance between adjacentnubs has a width greater than 2 mm, in particular between 3 mm to 9 mm,preferably between 4 mm to 8 mm, more preferably between 5 mm to 6 mm.This clear distance also determines the width of the channel section anddefinition with the free space to the adjacent nubs.

In addition, in a further preferred embodiment, it is provided that theratio of the area of the nub bottoms and/or nub end faces of all studsto the carrier web plane is preferably between 40% and 70%, furtherpreferably between 45% and 55%, and in particular at least substantially50%. In tests carried out, it has been found that, if the aforementionedratios are observed, particularly good decoupling values can be achievedwith a simultaneously particularly firm fixing of the tile adhesive tothe decoupling web. The aforementioned ratios, together with the nubheight, also decisively define, among other things, the requiredquantity of tile adhesive used to bond the decoupling web and thecovering element. On the carrier plate, in particular, a loaddistribution of the occurring tensile stress is made possible by thechannels, because preferably a compensation of the occurring stress iscarried out. In tests, it was ultimately found that the ratio of 40% to60%, preferably 45% to 55%, is particularly advantageous and exhibitsgood decoupling properties and good adhesive tensile strength.

Moreover, it is understood that any intermediate intervals andindividual values are included in the aforementioned intervals and rangelimits and are to be considered disclosed as essential to the invention,even if these intermediate intervals and individual values are notspecifically indicated.

Further features, advantages and possible applications of the presentinvention will be apparent from the following description of examples ofembodiments with reference to the drawing and the drawing itself. Inthis connection, all the features described and/or illustratedconstitute, individually or in any combination, the subject-matter ofthe present invention, irrespective of their summary in the claims andtheir relation back.

It shows:

FIG. 1 a schematic representation of a layered structure of the carrierweb according to the invention,

FIG. 2 a schematic representation of a further embodiment of a layeredstructure of the carrier web according to the invention,

FIG. 3 a schematic representation of a further embodiment of a layeredstructure of the carrier web according to the invention,

FIG. 4 a schematic representation of a further embodiment of a layeredstructure of the carrier web according to the invention,

FIG. 5 a schematic cross-sectional view of a decoupling web according tothe invention for use for a tile covering,

FIG. 6 a schematic perspective view of a decoupling web according to theinvention,

FIG. 7 a schematic perspective view of a further embodiment of adecoupling web according to the invention, and

FIG. 8 a schematic perspective view of a further embodiment of adecoupling web according to the invention.

FIG. 6 shows a decoupling web 1. The decoupling web 1 has a carrier web3 and a plurality of nubs 5 projecting from the carrier web plane 4. Thecarrier web 3 has as material a plastic and/or consists of a plastic. Inparticular, the carrier web 3 may comprise a thermoplastic material.

FIG. 5 shows that the decoupling web 1 is provided for use for a surfacecovering structure 2 which can be covered with covering elements, in theillustrated embodiment example with tiles 14. FIG. 5 shows that a tilecovering is provided as the surface covering structure 2.

The carrier web 3 shown in the embodiment examples has as material acopolymer containing ethylene and vinyl acetate and/or consists thereof.In particular, the copolymer comprising ethylene and vinyl acetate isformed as a copolymer of ethylene and vinyl acetate, preferably asethylene-vinyl acetate (EVA, EVAC).

The carrier web 3 may comprise as further material at least onethermoplastic polymer and/or elastomer. In particular, the thermoplasticpolymer and thus the further material may be HDPE, PE and/or PP. Thecopolymer comprising ethylene and vinyl acetate may be blended with thefurther thermoplastic material. Moreover, the further thermoplasticplastic material of the carrier web 3 may have a mass fraction of thematerial of the carrier web 3 between 40 to 95 wt. %. The proportion ofthe material of the carrier web 3 of the further thermoplastic plasticmaterial, in particular in relation to the copolymer comprising ethyleneand vinyl acetate, can be selected depending on the applicationenvironment or the intended use.

Not shown is that the copolymer comprising ethylene and vinyl acetatemay have a mass fraction of the material of the carrier web 3 of atleast 5 wt. %, and in further embodiments between 25 wt. % to 55 wt. %.

Furthermore, it is not shown that the copolymer comprising ethylene andvinyl acetate has a vinyl acetate content of at least 5% and, in furtherembodiments, between 16% and 30%—based on the copolymer comprisingethylene and vinyl acetate. In particular, the copolymer comprisingethylene and vinyl acetate is thermoplastic.

In FIG. 1, it is shown that the carrier web 3 has a single-layerstructure and is thus formed by the material layer A. In this context,it is understood that this layered structure can also be produced by amulti-layer extrusion die, wherein the layer A can consequently beapplied in several layers of the same material composition. Ultimately,the material layer A has an at least substantially homogeneous materialdistribution.

FIG. 2 shows that the carrier web 3 has at least a two-layered layerstructure 6. In FIG. 2, layers A and B are provided, wherein both layerA and layer B are formed as outer layers, i.e. form an outer side of thecarrier web 3. The layers A and B have a different material compositionfrom each other. The layer A, shown in FIG. 2, may face the tileadhesive.

Furthermore, at least one layer A and/or B of the carrier web 3 maycomprise the copolymer comprising ethylene and vinyl acetate. Inparticular, the outer layer A comprises the copolymer comprisingethylene and vinyl acetate. In FIG. 2, a layer structure in the form A-Bis shown. Here, the layer B may or may not have the copolymer comprisingethylene and vinyl acetate.

FIG. 3 shows a layered structure in the form A-B-A, wherein the outerlayers A may be of the same or identical design with respect to theirlayer thickness 7 and/or their material composition. The layers A shownin FIG. 3 may have a material composition differing from that of thelayer B.

FIG. 4 shows a layer structure 6 with the layer sequence A-B-C. Here,the layer C may have a material composition and/or layer thickness 7that differs from the outer layer A and/or from the layer B. Inparticular, the outer layer C has a modified proportion of the copolymercomprising ethylene and vinyl acetate or no proportion at all of thecopolymer comprising ethylene and vinyl acetate.

In further embodiments, it may be provided that only an outer layer Aand/or the outer layers A, A or A, C comprise and/or have the copolymercomprising ethylene and vinyl acetate. In this context, the furtherlayer B provided between the outer layers (A or A, A or A, C), inparticular the centrally enclosed layer B, may not comprise any portionof the copolymer comprising ethylene and vinyl acetate.

Furthermore, in further embodiments it may be provided that each layerA, B or A, B, C of the layer structure 6 of the carrier web 3 maycomprise the copolymer comprising ethylene and vinyl acetate, whereinthe individual layers may be different with respect to their materialcomposition, their properties and/or their layer thicknesses 7. Inprinciple, it is of course also possible that, in addition to the layersA, B, C, a plurality of further layers can be provided which differ withrespect to or from the layers A, B and/or A, B, C by their materialcomposition, their properties and/or their layer thickness 7.

The layer A, B and/or C comprising the copolymer comprising ethylene andvinyl acetate may have a mass fraction of the copolymer comprisingethylene and vinyl acetate in the material of the respective layer A, Band/or C of at least 5% by weight. In particular, the mass fraction ofthe copolymer comprising ethylene and vinyl acetate in the outer layer Aand/or in the outer layer C is between 30 to 50 wt. %. In theaforementioned layers A, B, C, as a further material—in addition to thecopolymer comprising ethylene and vinyl acetate—at least onethermoplastic plastic material (in particular a polymer and/orelastomer) may be provided. The plastic material may be HDPE, PE and/orPP. The copolymer comprising ethylene and vinyl acetate may be blendedwith the further plastic material. The further plastic material may havea mass fraction of between 50 to 90 wt. % of the material of the carrierweb 3 and/or of the material of the layer A, B and/or C comprising thecopolymer comprising ethylene and vinyl acetate. Very preferably, themass fraction of the further plastic layer in layer B is greater thanthe mass fraction of the copolymer comprising ethylene and vinylacetate.

Furthermore, in further embodiments, it may be provided that the massfraction of the copolymer comprising ethylene and vinyl acetate in theouter layers A and/or C is greater, preferably by at least 50%, than themass fraction of the copolymer comprising ethylene and vinyl acetate inthe central and/or further layer B, respectively.

In FIGS. 2 to 4 it is shown that the outer layer A and/or the outerlayers A, A and/or A, C have at least 10%, in the embodiment exampleshown at least substantially 50%, of the layer thickness 7 of a further,in particular central, layer B. Accordingly, the material of the layer Bmay have a significantly higher proportion of the total material of thecarrier web 3 or of the layer structure 6 of the carrier web 3, inparticular of up to 80% and/or of at least 40%.

It is not shown that the carrier web 3, in particular the decoupling web1, has an adhesive tensile strength of greater than 0.1 N/mm², infurther embodiments between 0.2 N/mm² to 5 N/mm².

Furthermore, it is not shown that the carrier web 3, in particular thedecoupling web 1, has a modulus of elasticity of less than 100 GPa, infurther embodiments between 0.05 to 2.5 GPa.

FIG. 5 shows that the decoupling web 1 comprises a fabric and/ornon-woven layer 8. In the illustrated embodiment example, a non-wovenlayer 8 is provided. The non-woven layer 8 is firmly connected to thecarrier web 3. In this regard, the non-woven layer 8 may be laminated tothe carrier web 3. In the illustrated embodiment example, the non-wovenlayer 8 is arranged at the nub end faces 10 and/or at the nub plane 11.

The non-woven layer 8 is arranged on an underground 17, as can be seenin FIG. 5. Thereby, the non-woven layer 8 may be bonded to theuntereground 17 via an adhesive layer. In the illustrated embodimentexample, the non-woven layer 8 is bonded to the underground 17 by meansof the tile adhesive 13.

In the embodiment example shown in FIG. 5, it may be provided that thetile 14 has a height of about 5 mm+/−3 mm. The height of the nubs 5 maybe about 4 mm. The tile adhesive 13 applied to the top of the carrierweb 4 may for example have a height of between 2 to 10 mm, in particularbetween 3 to 6 mm. The thickness of the carrier web 3 and/or thenon-woven layer 8 may be about 0.5 mm. On the underside of the non-wovenlayer 8, the tile adhesive layer may have a height of between 3 and 6mm.

FIGS. 6 to 8 show that the nubs 5 are arranged at a distance from oneanother. The nubs 5 extend both in the longitudinal direction L andtransversely to the longitudinal direction L. In the present case, thenubs 5 have an ordered arrangement. However, this need not be the case.Unordered arrangements of the nubs 5 are also possible. The nubs 5 havea distance 9 from the upper carrier web plane 5 and a lower nub plane 11formed by the outer nub end faces 10. The nub plane 11 is formed by thenub end faces 10.

FIG. 6 shows that the nubs 5 form an at least substantially cube-shapeddepression. FIGS. 7 and 8 show that the nubs 5 have an at leastsubstantially three-legged cross-sectional shape. In principle, however,other shapes are also possible.

The distance 9 from the upper carrier web plane 5 is ultimately definedby the height of the side walls 16 of the nub 5, the side walls 16connecting the carrier web plane 4 to the nub plane 11. The side walls16 ultimately define the nub interior 15 of the nubs.

FIG. 5 shows that the nubs 5 and/or at least one nub 5 has an undercut12 at least in sections. In the illustrated embodiment example, theundercut 12 is formed in the shape of a crescent or an arcuate section.An undercut 12 having an at least substantially rectangularcross-sectional shape is also possible in principle.

In FIG. 8, it is shown that projections 18 are provided on the nub endfaces 11. Ultimately, the projections 18 can have any shape andultimately serve to structure the nub base.

EXECUTION EXAMPLE

A number of embodiments according to the invention are given below,which are compared with a comparative example 0 (not according to theinvention).

The embodiments according to the invention to be compared with eachother and the comparative example 0 not according to the invention havean at least substantially identical construction of the shape of thedecoupling web, the nub shapes of the examples corresponding to eachother in geometrical form. The embodiments ultimately differ only withrespect to their material composition.

The carrier webs of the decoupling web are manufactured by extrusion ofthermoplastic material and subsequent shaping on a vacuum deep roll. Toform a decoupling web, a spunbonded polypropylene fleece is laminated tothe carrier web on the nub plane. The extrusion is carried out with amulti-layer die, wherein the “single-layer structure” is also obtainedby the multi-layer extrusion die, although the same material compositionis ultimately present in the applied layers, so that the multi-layerextrusion die can then produce a single-layer structure.

Furthermore, the embodiments to be compared have at least substantiallythe same overall layer thickness of the carrier web, and in the case ofa multilayer structure, the ratio of the layers is indicated in thetable below. The nub shape of the embodiments corresponds at leastsubstantially to the square nub shown in FIG. 6.

Furthermore, the materials EVA28, EVA18 and HDPE of the embodimentscorrespond to each other.

The embodiments have the following material composition:

Example Layer A Layer B Ratio A:B:A Comparison 100% HDPE / / example 0Example 1 70% HDPE / / 30% EVA28 Example 2 60% HDPE / / 40% EVA28Example 3 50% HDPE / / 50% EVA28 Example 4 70% HDPE 100% HDPE0.25:0.5:0.25 30% EVA28 Example 5 60% HDPE 100% HDPE 0.25:0.5:0.25 40%EVA28 Example 6 50% HDPE 100% HDPE 0.25:0.5:0.25 50% EVA28 Example 7 70%HDPE 90% HDPE 0.25:0.5:0.25 30% EVA28 10% EVA28 Example 8 60% HDPE 95%HDPE 0.25:0.5:0.25 40% EVA28 5% EVA28 Example 9 70% HDPE / / 30% EVA18Example 10 60% HDPE / / 40% EVA18 Example 11 60% HDPE 100% HDPE0.15:0.7:0.15 40% EVA28 Example 12 30% HDPE 100% HDPE 0.15:0.7:0.15 70%EVA18 Example 13 30% HDPE 100% HDPE 0.3:0.7:0 70% EVA18 Example 14 30%HDPE 100% HDPE 0.2:0.8:0 70% EVA18

In examples 12 and 13, a two-layer structure is provided, namely a layerstructure of the form AB. A spunbonded layer comprising polypropylene isarranged, in particular laminated, on the layer B.

HDPE is provided as the thermoplastic further plastic material and alsoas the material for the comparative examples not according to theinvention. The copolymer comprising ethylene and vinyl acetate is formedas ethylene-vinyl acetate and has a vinyl acetate content of at leastsubstantially 28% based on the copolymer of ethylene and vinyl acetate.This material is referred to as “EVA28”. Another copolymer comprisingethylene and vinyl acetate is formed as ethylene-vinyl acetate and has avinyl acetate content of at least substantially 18% based on thecopolymer of ethylene and vinyl acetate. This material is referred to as“EVA18”. When the copolymer of ethylene and vinyl acetate is added tothe thermoplastic material, it is envisaged that it is admixed with thethermoplastic material prior to extrusion of the carrier web. Extrusionis performed with both the thermoplastic resin material and thecopolymer of ethylene and vinyl acetate.

The above-mentioned design examples have been examined with regard todifferent criteria. The adhesive tensile strength has been determinedaccording to DIN EN 12004-02:2017-05. Furthermore, the modulus ofelasticity has been determined to determine the flexibility. Inaddition, the decoupling properties have been investigated when usingthe decoupling membrane as a decoupling underlay for a tile covering.Furthermore, the adhesion to the tile adhesive of the decouplingmembrane has been determined. The water tightness has also beendetermined.

The results table shown below relates the experimental results relativeto each other. The following results can be achieved:

-   -   −−−: unsatisfactory result    -   −−: unsatisfactory result    -   ∘: satisfactory result    -   +: good result    -   ++: very good result

The table below illustrates the results:

Adhesive Adhesion tensile to the tile Water- Example strengthFlexibility adhesive density Decoupling Comparison ∘ ∘ − ++ ∘ example 0Example 1 ∘ + +/++ ++ +/++ Example 2 + ++ ++ ++ ++ Example 3 ++ ++ ++++ + Example 4 + ∘/+  + ++ + Example 5 ++ + ++ ++ ++ Example 6 ++ + ++++ ++ Example 7 + + +/++ ++ +/++ Example 8 ++ +/++ ++ ++ ++ Example 9 ∘∘ ∘ ++ + Example 10 ∘ + + ++ +/++ Example 11 ++ +/++ ++ ++ +/++ Example12 ++ +/++ ++ ++ ++ Example 13 ++ + ++ ++ +/++ Example 14 ++ +/++ ++ ++++

The above results illustrate that by adding the copolymer containingethylene and vinyl acetate to the material of the carrier web accordingto the invention, both the adhesive tensile strength and the flexibility(by reducing the modulus of elasticity) can be improved. Even withincreasing amounts of the copolymer containing ethylene and vinylacetate (EVA28) only in the outer layers (layer A), very good adhesivetensile strengths can be achieved. Even up to 50% of the copolymercontaining ethylene and vinyl acetate (EVA28) or even up to 70% of thecopolymer containing ethylene and vinyl acetate (EVA18) can be added tothe outer layer A without the decoupling web becoming too soft.

Furthermore, even better flexibility results are obtained if the centrallayer B sandwiched between the outer layers A also contains thecopolymer comprising ethylene and vinyl acetate.

Alternatively, very good results are also achieved if, in a two-layerstructure (AB), only the outer layer A contains the copolymer comprisingethylene and vinyl acetate.

Ultimately, the water resistance remains virtually unaffected by theaddition of the copolymer containing ethylene and vinyl acetate.

In addition to the adhesive tensile strength, the addition of thecopolymer comprising ethylene and vinyl acetate can also improve theadhesion to the tile adhesive and the decoupling properties. Thisresults in an improved application and use of the decoupling sheetaccording to the invention.

REFERENCE LIST

1 Decoupling web

2 Surface covering structure

3 Carrier web

4 Carrier web plane

5 Nubs

6 Layer structure

7 Layer thickness

8 Nonwoven layer

9 Distance

10 Nub end faces

11 Nub plane

12 Undercut

13 Tile adhesive

14 Tile

15 Nub interior

16 Side wall

17 Underground

18 Projection

A Layer

B Layer

C Layer

L Longitudinal direction

1. A decoupling web, in particular intended for use for a surfacecovering structure which can be covered with covering elements,preferably tile coverings, having a carrier web and a multiplicity ofnubs projecting from the carrier web plane, the carrier web comprisingas material a, preferably thermoplastic, plastic, wherein the carrierweb comprises as material a copolymer comprising ethylene and vinylacetate, in particular a copolymer of ethylene and vinyl acetate,preferably ethylene-vinyl acetate (EVA), and/or consists thereof.
 2. Thedecoupling web according to claim 1, wherein the carrier web comprisesas further material at least one thermoplastic polymer and/or elastomer,in particular hard polyethylene (HDPE), polyethylene (PE) and/orpolypropylene (PP), in particular wherein the copolymer containingethylene and vinyl acetate is mixed with the further material and/orwherein the further material has a mass fraction of the material of thecarrier web of at least 20 wt. %, preferably between 30 wt. % and 99 wt.%, further preferably between 40 wt. % and 95 wt. %, further preferablybetween 50 wt. % and 80 wt. %, preferably between 30 wt. % and 99 wt. %,further preferably between 40 wt. % and 95 wt. %, further preferablyfurther between 50 wt. % and 80 wt. %.
 3. The decoupling web accordingto claim 1, wherein the copolymer comprising ethylene and vinyl acetatehas a mass fraction in the material of the carrier web of at least 5 wt.%, preferably between 10 wt. % to 80 wt. %, more preferably between 20wt. % to 60 wt. %, more preferably further between 25 wt. % to 55 wt. %.4. The decoupling web according to claim 1, wherein the copolymercomprising ethylene and vinyl acetate has a vinyl acetate content of atleast 5%, preferably between 10% and 50%, more preferably between 12%and 40%, further preferably between 16% and 30%, and in particular atleast substantially from 25% to 29%, in particular based on thecopolymer comprising ethylene and vinyl acetate.
 5. The decoupling webaccording to claim 1, wherein the carrier web has an at least two-layerlayer structure, at least two layers (A, B) having a materialcomposition differing from one another.
 6. The decoupling web accordingto claim 1, wherein at least one layer (A, B) of the carrier webcomprises the copolymer comprising ethylene and vinyl acetate, inparticular wherein at least one outer layer (A) comprises the copolymercomprising ethylene and vinyl acetate and, preferably, wherein a layerstructure A-B-A or A-B is provided.
 7. The decoupling web according toclaim 1, wherein only one outer layer (A) and/or the outer layers (A, A)comprise(s) the copolymer comprising ethylene and vinyl acetate or thateach layer (A, B) of the layer structure of the carrier web comprisesthe copolymer comprising ethylene and vinyl acetate.
 8. The decouplingweb according to claim 1, wherein the layer (A, B) comprising thecopolymer comprising ethylene and vinyl acetate has a mass fraction ofthe copolymer comprising ethylene and vinyl acetate in the material ofthe layer (A, B) of at least 5 wt. %, preferably between 10 wt. % and 80wt. %, more preferably between 20 wt. % and 60 wt. %, more preferablybetween 25 wt. % and 55 wt. %, in particular wherein at least onethermoplastic polymer and/or elastomer, in particular hard polyethylene(HDPE), polyethylene (PE) and/or polypropylene (PP), is provided as thefurther material and, preferably, wherein the copolymer containingethylene and vinyl acetate is mixed with the further material and/or thefurther material has a mass fraction of the material of the carrier weband/or of the material of the layer (A, B) containing the copolymercontaining ethylene and vinyl acetate of at least 20 wt. %, preferablybetween 30 wt. % and 99 wt. %, more preferably between 40 wt. % and 95wt. %, further preferably between 50 wt. % and 80 wt. %.
 9. Thedecoupling web according to claim 1, wherein the outer layer (A) and/orthe outer layers (A, A) has/have at least 10%, preferably between 10%and 90%, more preferably between 40% and 60% and in particular at leastsubstantially 50%, of the layer thickness of a further, in particularcentral, layer (B).
 10. The decoupling web according to claim 1, whereinthe carrier web, in particular the decoupling web, has an adhesivetensile strength of greater than 0.1 N/mm², preferably greater than 0.2N/mm², more preferably between 0.2 N/mm² and 5 N/mm².
 11. The decouplingweb according to claim 1, wherein the carrier web, in particular thedecoupling web, has a modulus of elasticity of less than 100 GPa,preferably less than 10 GPa, more preferably between 0.01 to 5 GPa andpreferably between 0.05 to 2.5 GPa.
 12. The decoupling web according toclaim 1, wherein the decoupling web has, in particular on the sideopposite the carrier web plane, a fabric and/or nonwoven layer, inparticular the nonwoven layer being firmly connected to the carrier web,in particular being laminated onto the carrier web.
 13. The decouplingweb according to claim 1, wherein the nubs are arranged at a distancefrom one another and, preferably, transversely to the longitudinaldirection (L) and in the longitudinal direction (L) of the decouplingweb, in particular wherein the nubs form a distance from the uppercarrier web plane and a lower nub plane formed by the outer nub endfaces.
 14. The decoupling web according to claim 1, wherein at least onenub has an undercut at least in sections.